The Effect Of Local Low-dose X-irreadiation For The Repair Of Spinal Cord Injury In Experiment By Olfactory Ensheathing Cells Transplantation

objective To investigate the effect of local low-dose X-irradiation for the repair of spinal cord injury in experiment by olfactory ensheathing cells transplantationMethods:48 Sprague-Dawley rats were subjected to spinal cord injury by modified weight dropping of Allen's. All animals were divided into 3 groups then randomly:A group was X-irradiation+OECs transplantation group, B group was OECs transplantation group, and C group was single injury group(control group). At the end of each week, animals were behaviorally tested, using Basso, Beattie, Bresnahan locomotor rating scale. The morphologic changes of axonal regeneration were observed by GFAP,MBP,NF200,P75 immunohistochemistry and HE staining at 2 and 8 weeks after spinal cord injury.Results: At the end of experiment, there were 9 rats died , 4 in A group, 3 in B group and 2 in C group respectively. The death rate was 18.75%. There were no significant differences in BBB score of each group at two weeks, but the BBB score of A and B group were significantly higher than that of C group at 8 weeks (P<0.05). The morphologic recovery of spinal cord injury in A group was better than that of C group (P<0.05). A large number of disorderly regeneration of axons can be observed in spinal cord injury center area of A group by X-irradiation at postoperative 2 and 8 weeks. And the survival of olfactory ensheathing cells were good by anti-NGFRp75 staining. However, the number of regenerated axons of B group was less than that of A group shown by NGFRp75 Anti-staining, showing a small amount of scar formation. There was only bits of axon regeneration and lots of scar formation in C group. Functional recovery of spinal cord injury in A group was better than that of B group,but there was no significant difference. The GFAP and NF of A and B groups were higher than that of C group at each time point of 2 and 8 weeks (P﹤0.05). The MBP of A and B groups decreased significantly than C group at 2 weeks(P﹤0.01, P﹤0.05); The MBP of A group decreased significantly than B and C groups at 8 weeks, and there was obvious difference (P﹤0.05);But no significant difference between B and C groups, and the MBP count of C group signnificantly increased as time.Conclusions1. Allen's weight-dropping is a good clinical relevance, repeated and objectively quantified model of rat SCI.2. OECs transplantation can promote significantly functional recovery following spinal cord injury, while the combined application of OECs transplantation and may cause a synergistic effect, and it could provide the theoretical basis and new direction in future.3. The merchanism of spinal cord injury repair may be related to the reduction of local glial scar formation and improvement of inhibitive micro-environment after intervention of a low dose of X-irradiation.